Anyone got any good books on evolution that are easy to understand?

One of my primary interests in life is animals. I love animals. I've been rooting for Punch the monkey that's been making the rounds online and I just find it fascinating that while monkeys aren't humans we still feel a connection with them more than other animals because they're primates and that makes us similar in some ways. I also find it interesting how there are so many branches in the evolutionary tree and I want to know why things like that exist. What caused humans to evolve into what they are today while other primates evolved into what they are today.